Hi,
I just found an easy way to transcribe voice memos with the basic functions of the Mac (Mountain Lion).
First of all, you need a recorder to take the memos. I record them using my iPhone and the included Voice Memo app. After syncing, the memos are shown in iTunes.
At this point, open a text document and prepare for transcription. Set your memo to play, and move the text document in the foreground. Listen to a sentence, then start Mac’s Dictation. When the Mac enters listening mode, iTunes (or any other music player) is automatically stopped. You can repeat the sentence and let the Mac listen to you.
Stop listening mode, and while the Mac is transcribing what you told, iTunes automatically starts playing again. Listen to another sentence, then let the Mac enter listening mode again.
I find it a very effective way of transcribing, while also correcting any mistake done when recording the memos.
Paolo